Astraia
Know your ring size to the millimetre, without leaving the house or guessing.
iOS and Android
free · no ads · no subscription
Astraia turns the phone you already own into an accurate measuring instrument. You calibrate the screen once against an object of known size — a credit card, a coin, a ruler — and the display becomes a true-scale surface. Then you measure an existing ring or your own finger directly on the glass, and read an exact inner diameter in millimetres, converted to US, UK, EU and Japanese sizes.
It is built for the person about to buy a ring online, often as a gift and often in secret, who would rather know than guess.
01
Calibrate the screen
A credit card, a coin from one of eleven regions, or any ruler. Astraia works out exactly how many pixels make a millimetre on your particular display, then remembers it.
02
Measure on the glass
Lay a ring flat on the screen and match the circle, or measure your finger against the on-screen rule. Both surfaces render at true physical size — nothing about them is scaled for looks.
03
Read a real number
An exact inner diameter in millimetres, adjusted for band width, converted to US, UK, EU and Japanese sizes. Save it, share it, or copy the specifications for a jeweller.
/screens
What Astraia collects: nothing.
how it is paid for
Free, and honest about why
Astraia costs nothing and shows no advertising. It earns through affiliate commission on a curated set of jewellery and fit products — so the moment you learn your size is also the moment you are shown something worth buying.
what that means for you
Tapping a product means leaving
A product link opens the retailer's own site, and from that point they see what their site normally sees. We receive aggregate commission reports only — never your name, address, payment details or order contents.
Commission disclosure: Aristourgima LLC participates in third-party affiliate programmes, including the Amazon Services LLC Associates Program. As an Amazon Associate we earn from qualifying purchases. Product suggestions shown in Astraia are affiliate links, at no additional cost to you.